exception - 为什么按下numlock会使OCaml opengl程序崩溃？

我没有任何关于openGL的经验，所以也许我只是想念一些东西。

我有使用lablGL的ocaml代码。编译我用

ocamlopt -I + lablGL lablglut.cmxa lablgl.cmxa gl.ml -o gl.opt

或者

ocamlc -I + lablGL lablglut.cma lablgl.cma gl.ml -o gl.byte

let keyboard ~key ~x ~y =
  match key with
    | 27 -> exit 0
    | _ -> ignore (Printf.printf "Key: %c %d pressed.\n%!" (char_of_int key) key)
;;

let keyboard_up ~key ~x ~y =
  match key with
    | _ -> ignore (Printf.printf "Key: %c %d released.\n%!" key (int_of_char key))
;;

let special ~key ~x ~y =
  try
    match key with
      | Glut.KEY_F1 -> Printf.printf "F1 pressed.\n%!"
      | Glut.KEY_F2 -> Printf.printf "F2 pressed.\n%!"
      | Glut.KEY_F3 -> Printf.printf "F3 pressed.\n%!"
      | Glut.KEY_F4 -> Printf.printf "F4 pressed.\n%!"
      | Glut.KEY_F5 -> Printf.printf "F5 pressed.\n%!"
      | Glut.KEY_F6 -> Printf.printf "F6 pressed.\n%!"
      | Glut.KEY_F7 -> Printf.printf "F7 pressed.\n%!"
      | Glut.KEY_F8 -> Printf.printf "F8 pressed.\n%!"
      | Glut.KEY_F9 -> Printf.printf "F9 pressed.\n%!"
      | Glut.KEY_F10 -> Printf.printf "F10 pressed.\n%!"
      | Glut.KEY_F11 -> Printf.printf "F11 pressed.\n%!"
      | Glut.KEY_F12 -> Printf.printf "F12 pressed.\n%!"
      | Glut.KEY_LEFT -> Printf.printf "Left pressed.\n%!"
      | Glut.KEY_UP -> Printf.printf "Up pressed.\n%!"
      | Glut.KEY_RIGHT -> Printf.printf "Right pressed.\n%!"
      | Glut.KEY_DOWN -> Printf.printf "Down pressed.\n%!"
      | Glut.KEY_PAGE_UP -> Printf.printf "PgUp pressed.\n%!"
      | Glut.KEY_PAGE_DOWN -> Printf.printf "PgDown pressed.\n%!"
      | Glut.KEY_HOME -> Printf.printf "Home pressed.\n%!"
      | Glut.KEY_END -> Printf.printf "End pressed.\n%!"
      | Glut.KEY_INSERT -> Printf.printf "Insert pressed.\n%!"
  with
    | Glut.BadEnum m -> Printf.printf "%s\n" m
;;

let () =
  ignore (Glut.init Sys.argv);
  ignore (Glut.createWindow ~title:"OpenGL Demo");
  GlClear.color (1.0, 1.0, 1.0);
  Glut.keyboardFunc ~cb:(keyboard);
  Glut.specialFunc ~cb:(special);
  Glut.displayFunc ~cb:(fun () -> GlClear.clear [ `color ]; Gl.flush ());
  Glut.mainLoop ()

现在是问题所在。禁用numlock时按numlock或任何其他numpad键会引发异常，从而使程序崩溃。尝试在特殊功能中捕获此异常无济于事。

这是示例运行。

> ./gl.opt
Up pressed.
Down pressed.
Key: 1 49 pressed.
Key: 2 50 pressed.
Fatal error: exception Glut.BadEnum("key in special_of_int")

有人可以向我解释为什么它如此工作以及如何解决吗？

最佳答案

根据this代码，似乎编写它的用户只是试图通过以下方式避免该错误:

let rec handlelablglutbug () =
    try
      Glut.mainLoop ();
    with Glut.BadEnum "key in special_of_int" ->
      showtext '!' " LablGlut bug: special key not recognized";
      Glut.swapBuffers ();
      handlelablglutbug ()
  in
  handlelablglutbug ();

这使我认为这是与glut库的ocaml端口有关的错误。因此无法进行无缝修复。

关于exception - 为什么按下numlock会使OCaml opengl程序崩溃？，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/3478623/